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#22
July 16th 03, 09:26 PM
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Dependence of the speed of light on the speed of the source.
On 16 Jul 2003 06:51:35 -0700, (George G. Dishman)
wrote: HW@..(Henri Wilson) wrote in message . .. On 14 Jul 2003 12:38:34 -0700, (George G. Dishman) wrote: HW@..(Henri Wilson) wrote in message . .. A__________C__________D--2v A__________C-v__________D--2v The proof is trivial. It requires no assumptions, just plain logic. If clock C is accelerated to velocity v, it ends up faster wrt A but slower wrt D. According to SR, its rate must both increase and decrease simultaneously. That is obviously impossible IN THE PHYSICAL sense. So no PHYSICAL change occurs in a clock as its speed changes. That's a nice example to look at the difference between SR and aether theories. In LET, the clock rate IS physically changed by some interaction with the aether. The paradox you present is resolved by the physical contraction of materials that is also produced by motion through the aether that causes speeds to be mis-measured and the delay due to the motion of the light miscalculated. It's all very messy really. The changes COULD BE real if aether existed. Exactly. On the other hand, SR says that the clock is unaffected by the motion in the sense that it produces the same number of ticks per unit of proper time. That is just another way of saying exactly what I am emphasizing here. Nothing PHYSICALLY happens to clocks or rods due to movement. Right, (though I have been a bit more careful in my wording). That's one of the main differences between LET and SR. The only way to compare two clocks in relative motion is by using a synchronising scheme as we have discussed before. The assumption in your paradox is that simultaneity is absolute while in SR it isn't. In the case of orbiting GPS clocks, they are effectively at rest wrt the ground clock since they return to the same point every exact orbit. No they are still moving as they pass that point. For example if you were stationary at that point in the orbit, a signal from the satellite would still be Doppler shifted as it approached and receded from you. However, that doesn't alter my point that your 'proof' is invalid because it makes the assumption of absolute simultaneity. You have already agreed that nothing physically changes due to speed. Now you want to deny that fact. I don't see why simultaneity should enter into this. If it did then all of the claims of SR would be wrong. Therefore, since their real rates did NOT change due to velocity, their observed rate changes can only be caused by gravity stress release. Therefore the claimed exactness of the 'GR correction' for these clocks is wrong since it relies on a non-existent 'velocity component'. If you want to call it 'observational', that's your choice. That aspect of GR is considered correct because it accurately predicts the value of the 'observational' effect. But in the case of GPS clocks it DOES NOT because the velocit component is non existent and They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. The need for the exact 'GR correction' has never been properly verified. The required correction is roughly the same order but the clocks are corrected at regular intervals anyway. The operators of the GPS stress that it is not a test of GR. because the accuracy of measurement has never been adequate for checking whether it is right or wrong. The GPS correction amounts to only 4cm per orbit. The clocks are regularly corrected empirically anyway. IIRC, it is about 44 microseconds per day and they are measured at the nanosecond level so the accuracy is better than 'adequate' by four orders of magnitude. There is a change in clock rate due to being in free fall. It just happens to be close to the GR correction at GPS orbits. We never hear anything about the 'correction' required for other orbits do we.. Why would that be? As far as the precession of mercury is concerned, all i can say is that if a theory is out by a factor of exactly two, one should go over the calculations and not throw out the whole theory. The Pound-Rebka experiment equally supports both GR and ballistic light theory. I don't want to extend the discussion to other experiments at present, those I cited make my point adequately. ... the corrections needed to GPS satellites are very accurately measured and also confirm the result. No they are not. They are not accurately measured? The clocks are monitored at the nanosecond level and have been for years. They are corrected empirically. If they don't give the right coordinates of a known location they are simply software adjusted. And the corrections are accurately recorded, those are in effect the experimental results. Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Not at all. We can see plenty of bright stars with our naked eyes. PM's will pick up millisecond pulses of their light quite easily. Well good luck getting it done. BTW, have you considered using the Moon itself as your gate by occultation? Hm. Maybe possible but I don't see a simple way to do it.. The exact distance from the earth would have to be known for each experiment. You can consider any two-way measurement to be a one-way measurement preceded by synchronising the clocks using the outgoing light, and all other methods are equivalent. That's Einstein's definition of clock synching, designed to make OWLS always equal to TWLS. It doesn't match reality and is the cause of all the trouble. You assume reality has it's own approved method for synchronising clocks? That's what I meant in the first post when I said "Before you can measure it, you have to define it. ... I don't mean the practical problems of synchronisation but what you are trying to achieve." It's harder than it looks ;-) Not at all. Clocks synched together should stay in absolute synch to within their known drift tolerances no matter how they are moved along reasonably flat gravity.. You again assume that reality has something you call "absolute synch". That need not be the case and SR strongly suggests it isn't. that's where it is wrong. The above procedure defines absolute synch. Synch two clocks together, move them apart and they should remain in absolute synch. Of course. The MMX was designed to measure OWLS anisotropy. To any non-indoctrinated person, its null result would suggest that either the theory behind the experiment was wrong or that OWLS is locally source dependent. Well certainly their theory was wrong since they expected a non-zero value. However there are many alternatives as well as Ritzian theory. LET and SR both predict a null result so out of four candidates, the MMX eliminates only one, the Galilean aether. Even that is very suspect. Sorry, I should have qualified that as the non-dragged Galilean aether. Well spotted. My theory is based on the notion that light speed is initially c relative it source but changes as it travels. I say that the 'stuff that photon fields are made of' constitutes a kind of medium which support light propagation itself. That sounds like the classical EM field. That's correct. Whatever makes 'space devoid of all matter' different from 'space devoid of all matter and EM' is what Haether is made of. Every ray of light contributes to this 'Haether', the density and local turbulence of which all contribute to a local light speed. Because the density of Haether is very rare in space, photons can be traveling at many different speeds through it but tend to eventually equilibrate to the local c (in light.secs or light minutes, for instance). Yes, I picked up that hence it explains the binary star evidence but does not yet explain Sagnac. My "as well as" meant you need to develop it to cover both aspects. I don't see how you can do that without losing source dependence but I'll leave that task to you. I will look into that. I think the rotation of the mirrors will explain everything. George Henri Wilson. See my animations at: http://www.users.bigpond.com/HeWn/index.htm 
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#23
July 17th 03, 08:37 PM
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Dependence of the speed of light on the speed of the source.
"Henri Wilson" HW@.. wrote in message ... On 16 Jul 2003 06:51:35 -0700, (George G. Dishman) wrote: HW@..(Henri Wilson) wrote in message . .. The changes COULD BE real if aether existed. Exactly. On the other hand, SR says that the clock is unaffected by the motion in the sense that it produces the same number of ticks per unit of proper time. That is just another way of saying exactly what I am emphasizing here. Nothing PHYSICALLY happens to clocks or rods due to movement. Right, (though I have been a bit more careful in my wording). That's one of the main differences between LET and SR. The only way to compare two clocks in relative motion is by using a synchronising scheme as we have discussed before. The assumption in your paradox is that simultaneity is absolute while in SR it isn't. In the case of orbiting GPS clocks, they are effectively at rest wrt the ground clock since they return to the same point every exact orbit. No they are still moving as they pass that point. For example if you were stationary at that point in the orbit, a signal from the satellite would still be Doppler shifted as it approached and receded from you. However, that doesn't alter my point that your 'proof' is invalid because it makes the assumption of absolute simultaneity. You have already agreed that nothing physically changes due to speed. I worded it more carefully, but yes I agree. Now you want to deny that fact. You lost me here, I haven't changed anything I said. Why do you think I have? I don't see why simultaneity should enter into this. To compare the rate of two clocks that to see if they are equal, first synchronise a tick of one clock with a tick of the other. If the next tick from the clocks is also in sync, the clocks are ticking at the same rate. The inequalities for slower or afster rates follow. In your paradox the clocks are in relative motion so even if the are co-located for a first reference tick, they will all be separated for the next tick, and if you have spatially separated clocks, you have to take simultaneity into account. I can suggest an analogy if it would help but some people don't like such 'tricks'. If it did then all of the claims of SR would be wrong. .... But in the case of GPS clocks it DOES NOT because the velocit component is non existent and They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. The need for the exact 'GR correction' has never been properly verified. The required correction is roughly the same order but the clocks are corrected at regular intervals anyway. The operators of the GPS stress that it is not a test of GR. The point remains, the clocks are moving as they pass that point in orbit so there is a velocity component. The clocks are built with a correction factor to compensate for the altered rate in orbit and adjustments are small in comparison to that offset. The adjustments are not just because of GR, the system is sensitive enough to need to be corrected for the gravitational influence of large masses such as mountain ranges so it might be difficult to use it experimentally to get an accurate confirmation, but it is easily enough to confirm the effect occurs beyond any shadow of a doubt. because the accuracy of measurement has never been adequate for checking whether it is right or wrong. The GPS correction amounts to only 4cm per orbit. The clocks are regularly corrected empirically anyway. IIRC, it is about 44 microseconds per day and they are measured at the nanosecond level so the accuracy is better than 'adequate' by four orders of magnitude. There is a change in clock rate due to being in free fall. It just happens to be close to the GR correction at GPS orbits. Exactly, GR predicts the total effect and it is a single theory, not separate effects. What other theories predict any gravitational effect? We never hear anything about the 'correction' required for other orbits do we.. Why would that be? Because there are few satellites in other orbits with atomic clocks on board and sophisticated methods for comparing sync. GLONASS is about 1000km lower and there may be papers on that but I haven't looked for them. Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Right, so why why did you suggest only sync mattered since "'Time' cancels out .." Not at all. We can see plenty of bright stars with our naked eyes. PM's will pick up millisecond pulses of their light quite easily. Well good luck getting it done. BTW, have you considered using the Moon itself as your gate by occultation? Hm. Maybe possible but I don't see a simple way to do it.. The exact distance from the earth would have to be known for each experiment. No you need two detectors at different locations on the Earth so that the same crater edge say occults two stars at the same instant on the Moon. It's just a thought, but it would have the advantage of transferring the problems to the Earth end and means you don't need any equipment on the Moon. You assume reality has it's own approved method for synchronising clocks? That's what I meant in the first post when I said "Before you can measure it, you have to define it. ... I don't mean the practical problems of synchronisation but what you are trying to achieve." It's harder than it looks ;-) Not at all. Clocks synched together should stay in absolute synch to within their known drift tolerances no matter how they are moved along reasonably flat gravity.. You again assume that reality has something you call "absolute synch". That need not be the case and SR strongly suggests it isn't. that's where it is wrong. The above procedure defines absolute synch. Synch two clocks together, move them apart and they should remain in absolute synch. Again, you assume nature "should" behave the way you want it to. In fact they always maintain sync in the same way that Einstein's method produces. Every ray of light contributes to this 'Haether', the density and local turbulence of which all contribute to a local light speed. Because the density of Haether is very rare in space, photons can be traveling at many different speeds through it but tend to eventually equilibrate to the local c (in light.secs or light minutes, for instance). Yes, I picked up that hence it explains the binary star evidence but does not yet explain Sagnac. My "as well as" meant you need to develop it to cover both aspects. I don't see how you can do that without losing source dependence but I'll leave that task to you. I will look into that. I think the rotation of the mirrors will explain everything. I have seen that argued before but never seen anyone make it work. When you know the path length and speed, the time follows. The only attempts I have seen have involved displacement of the point of reflection on the mirror and I think that usually gives a second order effect, certainly not enough to predict what is observed. I'll be very interested to see how you tackle it. George
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#24
July 17th 03, 11:36 PM
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Dependence of the speed of light on the speed of the source.
On Thu, 17 Jul 2003 20:37:14 +0100, "George Dishman"
wrote: "Henri Wilson" HW@.. wrote in message ... On 16 Jul 2003 06:51:35 -0700, (George G. Dishman) wrote: No they are still moving as they pass that point. For example if you were stationary at that point in the orbit, a signal from the satellite would still be Doppler shifted as it approached and receded from you. However, that doesn't alter my point that your 'proof' is invalid because it makes the assumption of absolute simultaneity. You have already agreed that nothing physically changes due to speed. I worded it more carefully, but yes I agree. Now you want to deny that fact. You lost me here, I haven't changed anything I said. Why do you think I have? This nonsense about simultaneity. If an observer takes into account the travel time of information to reach him, the problem disappears. I don't see why simultaneity should enter into this. To compare the rate of two clocks that to see if they are equal, first synchronise a tick of one clock with a tick of the other. If the next tick from the clocks is also in sync, the clocks are ticking at the same rate. The inequalities for slower or afster rates follow. In your paradox the clocks are in relative motion so even if the are co-located for a first reference tick, they will all be separated for the next tick, and if you have spatially separated clocks, you have to take simultaneity into account. If you correct for information travel time using the DOPPLER expression the problem disappears. A moving rod will appear to have a different length even though we know it has not physically changed. There is no need to invoke SR. All one needs is the linear doppler term to get the right answer. Another way is to use a 'Henri Wilson reference frame'. My frames can be used anywhere in flat gravity. They contain an infinite grid of fixed 'perfect' clocks, all presynched and all subsequently moved carefully into position. All readings are done via these clocks and the information later relayed to me. That method provides me with instantaneous readings throughout parts of the universe. I can suggest an analogy if it would help but some people don't like such 'tricks'. If it did then all of the claims of SR would be wrong. ... But in the case of GPS clocks it DOES NOT because the velocit component is non existent and They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. The need for the exact 'GR correction' has never been properly verified. The required correction is roughly the same order but the clocks are corrected at regular intervals anyway. The operators of the GPS stress that it is not a test of GR. The point remains, the clocks are moving as they pass that point in orbit so there is a velocity component. That is a purely Newtonian doppler effect. You have agreed that the clocks have not PHYSICALLY changed due to their movement. The clocks are built with a correction factor to compensate for the altered rate in orbit and adjustments are small in comparison to that offset. The adjustments are not just because of GR, the system is sensitive enough to need to be corrected for the gravitational influence of large masses such as mountain ranges so it might be difficult to use it experimentally to get an accurate confirmation, but it is easily enough to confirm the effect occurs beyond any shadow of a doubt. The clocks change rates because they are relieved of gravitational compression. because the accuracy of measurement has never been adequate for checking whether it is right or wrong. The GPS correction amounts to only 4cm per orbit. The clocks are regularly corrected empirically anyway. IIRC, it is about 44 microseconds per day and they are measured at the nanosecond level so the accuracy is better than 'adequate' by four orders of magnitude. There is a change in clock rate due to being in free fall. It just happens to be close to the GR correction at GPS orbits. Exactly, GR predicts the total effect and it is a single theory, not separate effects. What other theories predict any gravitational effect? The fact that the required correction for GPS orbits happens to be close to the GR prediction is purely coincidental. It even has to includes the non-existent velocity component to make it anywhere near right. What about other orbits anyway? I say a clock in free fall will always shift by the same amount. We never hear anything about the 'correction' required for other orbits do we.. Why would that be? Because there are few satellites in other orbits with atomic clocks on board and sophisticated methods for comparing sync. GLONASS is about 1000km lower and there may be papers on that but I haven't looked for them. It does not use a GR correction. The system works perfectly well without it. Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Right, so why why did you suggest only sync mattered since "'Time' cancels out .." It is vital that all the orbiting clocks are in close synch with each other. Not at all. We can see plenty of bright stars with our naked eyes. PM's will pick up millisecond pulses of their light quite easily. Well good luck getting it done. BTW, have you considered using the Moon itself as your gate by occultation? Hm. Maybe possible but I don't see a simple way to do it.. The exact distance from the earth would have to be known for each experiment. No you need two detectors at different locations on the Earth so that the same crater edge say occults two stars at the same instant on the Moon. It's just a thought, but it would have the advantage of transferring the problems to the Earth end and means you don't need any equipment on the Moon. Yes that might be a distinct possibility. We would still have to know the exact distances but that would be relatively easy. Actually, if we could find two suitable sources which were exactly aligned parallel to a crater rim, the experiment could be carried out at one location on Earth. It would involve monitoring the intensity decay curves of the two images. You assume reality has it's own approved method for synchronising clocks? That's what I meant in the first post when I said "Before you can measure it, you have to define it. ... I don't mean the practical problems of synchronisation but what you are trying to achieve." It's harder than it looks ;-) Not at all. Clocks synched together should stay in absolute synch to within their known drift tolerances no matter how they are moved along reasonably flat gravity.. You again assume that reality has something you call "absolute synch". That need not be the case and SR strongly suggests it isn't. that's where it is wrong. The above procedure defines absolute synch. Synch two clocks together, move them apart and they should remain in absolute synch. Again, you assume nature "should" behave the way you want it to. In fact they always maintain sync in the same way that Einstein's method produces. NO THEY DO NOT. Einstein would resynch them when they were in position. There is no 'checking' and correcting in my method. The clocks are simply ASSUMED to have remained in synch. They are brought together regularly for comparison and then corrected if necessary. Every ray of light contributes to this 'Haether', the density and local turbulence of which all contribute to a local light speed. Because the density of Haether is very rare in space, photons can be traveling at many different speeds through it but tend to eventually equilibrate to the local c (in light.secs or light minutes, for instance). Yes, I picked up that hence it explains the binary star evidence but does not yet explain Sagnac. My "as well as" meant you need to develop it to cover both aspects. I don't see how you can do that without losing source dependence but I'll leave that task to you. I will look into that. I think the rotation of the mirrors will explain everything. I have seen that argued before but never seen anyone make it work. When you know the path length and speed, the time follows. The only attempts I have seen have involved displacement of the point of reflection on the mirror and I think that usually gives a second order effect, certainly not enough to predict what is observed. I'll be very interested to see how you tackle it. If you consider a rotating, four 45deg mirror configuration, the actual source velocity doesn't play any part. It is the peripheral velocity of the first mirror that would contribute to the first c+v effect. The analysis becomes a bit messy after that because all the angles change slightly during the light travel time. I am pretty sure that the fringe shift would occur even with source dependency. George Henri Wilson. See my animations at: http://www.users.bigpond.com/HeWn/index.htm
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#25
July 18th 03, 09:27 AM
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Dependence of the speed of light on the speed of the source.
Henri Wilson (HW@..), in article , wrote:
They tend to be more demonstrations than experiments but the corrections needed to GPS satellites are very accurately measured and also confirm the result. No they are not. The GPS is not designed to be a verification of GR. It would hardly be the first time that data had more than one interpretation, or that an implementation of one branch of science led to data for another.
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#26
July 18th 03, 01:02 PM
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Dependence of the speed of light on the speed of the source.
'' wrote:
Henri Wilson (HW@..), in article , wrote: No they are not. The GPS is not designed to be a verification of GR. It would hardly be the first time that data had more than one interpretation, or that an implementation of one branch of science led to data for another. Ref: Hartle, "Gravity: An Introduction to Einstein's General Relativity", Addison Wesley (2003) The difference between rates at which signals are emitted and received at two locations with different gravitational potentials is minute in laboratory circumstances. Yet take these differences into account is crucial for the operation of the Global Positioning System (GPS) used every day. If the relativistic effects of time dilation and the gravitational effects are not properly taken into account. the system would fail after only a fraction of an hour. The GPS consists of a constellation of satellites, each in a half sidereal day orbit about the Earth in a total of six orbital planes. Each satellite carries accurate atomic clocks that keep proper time on a satellite to accuracies of a few parts in 10^13 over a few weeks. Corrections uploaded several times a day from the ground enable accurate time to be kept over longer periods. The details of operation of the system are complex, see for example the nearly 800 pages of detail in Parkinson and Spilker (1996), but the basic idea is easily explained in an idealization of the real situation. Imagine an inertial frame in which the center of the Earth is approximately at rest for the time it takes a signal to propagate from a satellite to the ground. Periodically each satellite sends out microwave signals encoded with the time and spacial location of emission in the coordinates of the inertial frame. An observer that receives a signal an interval of time later can calculate his or her distance from the satellite by multiplying that time interval by the speed of light c. By using the signal from three satellites the observer's position in space can be narrowed down to the possible intersection points of three spheres. By using four satellites, the observer's position in both space and time can be fixed, even without the observer possessing an accurate clock, giving a complete location in spacetime. Signals from additional satellites reduce uncertainty further. Proper time on the satellite clocks has to be corrected to give the time of the inertial frame for at least two reasons: time dilation of special relativity and the effects of the Earth's gravitational field. to understand this, suppose a GPS satellite emits signals at a constant rate as measured by its clock. Suppose further that these are monitored by a distant observer at rest in the inertial frame. A clock of this observer, at rest and far from any source of gravitational effects, measures the time of the inertial frame. The signals will be received at a slower rate than they were emitted. Time dilation of the moving satellite clock is one reason. But another is the difference between the rates of emission an reception because the satellite is lower in the gravitational potential of the Earth than the distant observer. Two corrections must therefore be applied to rate of satellite time to get the time in the inertial frame. These corrections are tiny by everyday standards, but a nanosecond is a significant time in GPS operation. A signal from a satellite travels 30 cm in a nanosecond. To meet the announced 2-m accuracy for military applications of the GPS, times and time differences must be known to accuracies of approximately 6 ns. Keeping time to that accuracy is not a problem for contemporary atomic clocks, but at these accuracies, both time dilation and the gravitational redshift become important for GPS operation. The actual GPS does not employ an inertial frame whose time is defined by clocks at infinity; rather it uses a frame rotating with the Earth whose time is defined by clocks on its surface. The rates of the satellite clocks must be corrected downward to keep the time of that frame. Further corrections are needed for the relativistic Doppler effect, the relativity of simultaneity, the Earth's rotation, the asphericity of the Earth's gravitational potential, the time delays from the index of refration of the Earth's ionosphere, satellite clock errors, etc.
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#27
July 18th 03, 05:15 PM
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Dependence of the speed of light on the speed of the source.
"Henri Wilson" HW@.. wrote in message ... On Thu, 17 Jul 2003 20:37:14 +0100, "George Dishman" wrote: "Henri Wilson" HW@.. wrote in message ... On 16 Jul 2003 06:51:35 -0700, (George G. Dishman) wrote: No they are still moving as they pass that point. For example if you were stationary at that point in the orbit, a signal from the satellite would still be Doppler shifted as it approached and receded from you. However, that doesn't alter my point that your 'proof' is invalid because it makes the assumption of absolute simultaneity. You have already agreed that nothing physically changes due to speed. I worded it more carefully, but yes I agree. Now you want to deny that fact. You lost me here, I haven't changed anything I said. Why do you think I have? This nonsense about simultaneity. If an observer takes into account the travel time of information to reach him, the problem disappears. It doesn't, relativity of simultaneity refers to what constitutes simultaneous events regardless of the method of measurement. Anyway, that is not denying that there is no physical change to the clock, I haven't changed my view on anything. I don't see why simultaneity should enter into this. To compare the rate of two clocks that to see if they are equal, first synchronise a tick of one clock with a tick of the other. If the next tick from the clocks is also in sync, the clocks are ticking at the same rate. The inequalities for slower or afster rates follow. In your paradox the clocks are in relative motion so even if the are co-located for a first reference tick, they will all be separated for the next tick, and if you have spatially separated clocks, you have to take simultaneity into account. If you correct for information travel time using the DOPPLER expression the problem disappears. You said you didn't see why simultaneity was relevant so I hope you see the role it plays now. In SR, simultaneity is not absolute. Whether Doppler is relevant in your theory is not relevant. You cannot disprove any theory if you start with an assumption that conflicts with the theory. Your proof assumes absolute simultaneity hence is invalid for SR. A moving rod will appear to have a different length even though we know it has not physically changed. There is no need to invoke SR. All one needs is the linear doppler term to get the right answer. Another way is to use a 'Henri Wilson reference frame'. My frames can be used anywhere in flat gravity. They contain an infinite grid of fixed 'perfect' clocks, all presynched and all subsequently moved carefully into position. All readings are done via these clocks and the information later relayed to me. That method provides me with instantaneous readings throughout parts of the universe. Fine, but none of that is relevant to SR so your proof is still invalid. If you want to prove SR is internally inconsistent, which is what you attempted above, you must limit yourself to the rules of SR. But in the case of GPS clocks it DOES NOT because the velocit component is non existent and They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. The need for the exact 'GR correction' has never been properly verified. The required correction is roughly the same order but the clocks are corrected at regular intervals anyway. The operators of the GPS stress that it is not a test of GR. The point remains, the clocks are moving as they pass that point in orbit so there is a velocity component. That is a purely Newtonian doppler effect. Then you admit the GPS clocks are affected by their motion? The Doppler shift is not the same as the Newtonian version. In particular the velocity component is not zero when the motion is perpendicular to the line of sight. You have agreed that the clocks have not PHYSICALLY changed due to their movement. I have said they tick at the same rate per unit of proper time. In my view that means they are not physically changed but "physically changed" is not a well defined term and some people would disagree with me even though they would agree with my more explicit statement, hence my care with the wording. The clocks are built with a correction factor to compensate for the altered rate in orbit and adjustments are small in comparison to that offset. The adjustments are not just because of GR, the system is sensitive enough to need to be corrected for the gravitational influence of large masses such as mountain ranges so it might be difficult to use it experimentally to get an accurate confirmation, but it is easily enough to confirm the effect occurs beyond any shadow of a doubt. The clocks change rates because they are relieved of gravitational compression. In my opinion they are not physically affected. The rate change comes from projecting from the world line of the clock onto a coordinate axis. because the accuracy of measurement has never been adequate for checking whether it is right or wrong. The GPS correction amounts to only 4cm per orbit. The clocks are regularly corrected empirically anyway. IIRC, it is about 44 microseconds per day and they are measured at the nanosecond level so the accuracy is better than 'adequate' by four orders of magnitude. There is a change in clock rate due to being in free fall. It just happens to be close to the GR correction at GPS orbits. Exactly, GR predicts the total effect and it is a single theory, not separate effects. What other theories predict any gravitational effect? The fact that the required correction for GPS orbits happens to be close to the GR prediction is purely coincidental. It even has to includes the non-existent velocity component to make it anywhere near right. We already discussed that: They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. You also said: That is a purely Newtonian doppler effect. which could not exist if the velocity was "non-existent". Please don't repeat errors after they have been corrected, it makes for a very boring and repetitive conversation. What about other orbits anyway? I say a clock in free fall will always shift by the same amount. We never hear anything about the 'correction' required for other orbits do we.. Why would that be? Because there are few satellites in other orbits with atomic clocks on board and sophisticated methods for comparing sync. GLONASS is about 1000km lower and there may be papers on that but I haven't looked for them. It does not use a GR correction. Really, I haven't found anything on the subject, can you tell me where you found this information please. The system works perfectly well without it. Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Right, so why why did you suggest only sync mattered since "'Time' cancels out .." It is vital that all the orbiting clocks are in close synch with each other. Of course, but it is also vital that they are accurately synchronised to Earth time in a manner that allows users to use them as a time reference. Most atomic clocks come with a GPS option for example. Hm. Maybe possible but I don't see a simple way to do it.. The exact distance from the earth would have to be known for each experiment. No you need two detectors at different locations on the Earth so that the same crater edge say occults two stars at the same instant on the Moon. It's just a thought, but it would have the advantage of transferring the problems to the Earth end and means you don't need any equipment on the Moon. Yes that might be a distinct possibility. We would still have to know the exact distances but that would be relatively easy. Actually, if we could find two suitable sources which were exactly aligned parallel to a crater rim, the experiment could be carried out at one location on Earth. It would involve monitoring the intensity decay curves of the two images. Exactly, and all that could be done with standard amateur astronomy kit. You see, I really was trying to be helpful, not just criticise your idea. You assume reality has it's own approved method for synchronising clocks? That's what I meant in the first post when I said "Before you can measure it, you have to define it. ... I don't mean the practical problems of synchronisation but what you are trying to achieve." It's harder than it looks ;-) Not at all. Clocks synched together should stay in absolute synch to within their known drift tolerances no matter how they are moved along reasonably flat gravity.. You again assume that reality has something you call "absolute synch". That need not be the case and SR strongly suggests it isn't. that's where it is wrong. The above procedure defines absolute synch. Synch two clocks together, move them apart and they should remain in absolute synch. Again, you assume nature "should" behave the way you want it to. In fact they always maintain sync in the same way that Einstein's method produces. NO THEY DO NOT. From the Hafele-Keating experiment to the BBC Christmas Lectures a few years ago, every test I know of has been consistent with YES THEY DO and outside the error bars of NO THEY DO NOT. Cite your experimental evidence if you disagree. Einstein would resynch them when they were in position. There is no 'checking' and correcting in my method. The clocks are simply ASSUMED to have remained in synch. They are brought together regularly for comparison and then corrected if necessary. snip I will look into [Sagnac]. I think the rotation of the mirrors will explain everything. I have seen that argued before but never seen anyone make it work. When you know the path length and speed, the time follows. The only attempts I have seen have involved displacement of the point of reflection on the mirror and I think that usually gives a second order effect, certainly not enough to predict what is observed. I'll be very interested to see how you tackle it. If you consider a rotating, four 45deg mirror configuration, the actual source velocity doesn't play any part. It is the peripheral velocity of the first mirror that would contribute to the first c+v effect. The analysis becomes a bit messy after that because all the angles change slightly during the light travel time. They do but the speed of the light leaving each mirror is c+v and the setup is symmetrical about the centre of each light path so the light approaches the next mirror at c+v. Since the mirror is moving at v, it approaches at a relative speed of c. It leaves at c relative to the mirror hence c+v again and so on. If the entire path is covered at c+v, there should be no shift. The change in angles is something to look at but the symmetry argument tends to cancel them out, a greater launch angle corresponds to a greater arrival angle at the next mirror. I am pretty sure that the fringe shift would occur even with source dependency. As I say, superficially it all cancels and there should be no shift. You could be right but I know it will be difficult to find an explanation. George.
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#28
July 18th 03, 11:24 PM
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Dependence of the speed of light on the speed of the source.
On Fri, 18 Jul 2003 17:15:04 +0100, "George Dishman"
wrote: "Henri Wilson" HW@.. wrote in message ... On Thu, 17 Jul 2003 20:37:14 +0100, "George Dishman" wrote: You lost me here, I haven't changed anything I said. Why do you think I have? This nonsense about simultaneity. If an observer takes into account the travel time of information to reach him, the problem disappears. It doesn't, relativity of simultaneity refers to what constitutes simultaneous events regardless of the method of measurement. Anyway, that is not denying that there is no physical change to the clock, I haven't changed my view on anything. I don't see why simultaneity should enter into this. To compare the rate of two clocks that to see if they are equal, first synchronise a tick of one clock with a tick of the other. If the next tick from the clocks is also in sync, the clocks are ticking at the same rate. The inequalities for slower or afster rates follow. In your paradox the clocks are in relative motion so even if the are co-located for a first reference tick, they will all be separated for the next tick, and if you have spatially separated clocks, you have to take simultaneity into account. If you correct for information travel time using the DOPPLER expression the problem disappears. You said you didn't see why simultaneity was relevant so I hope you see the role it plays now. In SR, simultaneity is not absolute. Whether Doppler is relevant in your theory is not relevant. You cannot disprove any theory if you start with an assumption that conflicts with the theory. Your proof assumes absolute simultaneity hence is invalid for SR. Of course there is absolute simultaneity. It's just that one cannot establish it if one uses light for communication. However if two clcoks ar synchedthen moved apart in flat gravity, then they can be assumed to be in absolute synch and, when at rest wrt each other, will establish absolute simultaneity at their locations. A moving rod will appear to have a different length even though we know it has not physically changed. There is no need to invoke SR. All one needs is the linear doppler term to get the right answer. Another way is to use a 'Henri Wilson reference frame'. My frames can be used anywhere in flat gravity. They contain an infinite grid of fixed 'perfect' clocks, all presynched and all subsequently moved carefully into position. All readings are done via these clocks and the information later relayed to me. That method provides me with instantaneous readings throughout parts of the universe. Fine, but none of that is relevant to SR so your proof is still invalid. If you want to prove SR is internally inconsistent, which is what you attempted above, you must limit yourself to the rules of SR. SR is a complete hoax. It relies on the misapprehension that falling raindrops take longer too reach the ground when you view them through your car window because they appear to move diagonally. The point remains, the clocks are moving as they pass that point in orbit so there is a velocity component. That is a purely Newtonian doppler effect. Then you admit the GPS clocks are affected by their motion? No. The clocks are not physically affected by their motion. Their readings have to be adjusted for transverse doppler when observed from Earth, that is all. The Doppler shift is not the same as the Newtonian version. In particular the velocity component is not zero when the motion is perpendicular to the line of sight. That is the SRian view. The Newtonian correction is quite easy to calculate. You have agreed that the clocks have not PHYSICALLY changed due to their movement. I have said they tick at the same rate per unit of proper time. In my view that means they are not physically changed but "physically changed" is not a well defined term and some people would disagree with me even though they would agree with my more explicit statement, hence my care with the wording. The SRian use of the word 'proper' is just a way around admitting that time rate of change is absolute. The clocks are built with a correction factor to compensate for the altered rate in orbit and adjustments are small in comparison to that offset. The adjustments are not just because of GR, the system is sensitive enough to need to be corrected for the gravitational influence of large masses such as mountain ranges so it might be difficult to use it experimentally to get an accurate confirmation, but it is easily enough to confirm the effect occurs beyond any shadow of a doubt. The clocks change rates because they are relieved of gravitational compression. In my opinion they are not physically affected. The rate change comes from projecting from the world line of the clock onto a coordinate axis. But they clearly emit an increased number of ticks per orbit when they are up there compared with before launch. That means they have increased their physical ticking rates. It has nothing to do with 'time changes' or fancy world lines. because the accuracy of measurement has never been adequate for checking whether it is right or wrong. The GPS correction amounts to only 4cm per orbit. The clocks are regularly corrected empirically anyway. IIRC, it is about 44 microseconds per day and they are measured at the nanosecond level so the accuracy is better than 'adequate' by four orders of magnitude. There is a change in clock rate due to being in free fall. It just happens to be close to the GR correction at GPS orbits. Exactly, GR predicts the total effect and it is a single theory, not separate effects. What other theories predict any gravitational effect? The fact that the required correction for GPS orbits happens to be close to the GR prediction is purely coincidental. It even has to includes the non-existent velocity component to make it anywhere near right. We already discussed that: They are still moving whether they return to the same point or not. Regardless, the values from the GR calculations when done in the manner prescribed by GR match the values observed. That is all that matters. GR says you treat the satellites as moving in the inertial frame so that is what you have to do, it is part of the theory. You also said: That is a purely Newtonian doppler effect. which could not exist if the velocity was "non-existent". Please don't repeat errors after they have been corrected, it makes for a very boring and repetitive conversation. What about other orbits anyway? I say a clock in free fall will always shift by the same amount. We never hear anything about the 'correction' required for other orbits do we.. Why would that be? Because there are few satellites in other orbits with atomic clocks on board and sophisticated methods for comparing sync. GLONASS is about 1000km lower and there may be papers on that but I haven't looked for them. It does not use a GR correction. Really, I haven't found anything on the subject, can you tell me where you found this information please. I thought it was pretty common knowledge. I will try to find a reference. The system works perfectly well without it. Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Right, so why why did you suggest only sync mattered since "'Time' cancels out .." It is vital that all the orbiting clocks are in close synch with each other. Of course, but it is also vital that they are accurately synchronised to Earth time in a manner that allows users to use them as a time reference. Most atomic clocks come with a GPS option for example. Their signals are simply 'software corrected' for current drift. Hm. Maybe possible but I don't see a simple way to do it.. The exact distance from the earth would have to be known for each experiment. No you need two detectors at different locations on the Earth so that the same crater edge say occults two stars at the same instant on the Moon. It's just a thought, but it would have the advantage of transferring the problems to the Earth end and means you don't need any equipment on the Moon. Yes that might be a distinct possibility. We would still have to know the exact distances but that would be relatively easy. Actually, if we could find two suitable sources which were exactly aligned parallel to a crater rim, the experiment could be carried out at one location on Earth. It would involve monitoring the intensity decay curves of the two images. Exactly, and all that could be done with standard amateur astronomy kit. You see, I really was trying to be helpful, not just criticise your idea. You have been helpful and I appreciate that. Your idea is probably just about as feasible as Romer's light speed measurements. Synch two clocks together, move them apart and they should remain in absolute synch. Again, you assume nature "should" behave the way you want it to. In fact they always maintain sync in the same way that Einstein's method produces. NO THEY DO NOT. From the Hafele-Keating experiment to the BBC Christmas Lectures a few years ago, every test I know of has been consistent with YES THEY DO and outside the error bars of NO THEY DO NOT. Cite your experimental evidence if you disagree. Einstein would resynch them when they were in position. There is no 'checking' and correcting in my method. The clocks are simply ASSUMED to have remained in synch. They are brought together regularly for comparison and then corrected if necessary. snip I will look into [Sagnac]. I think the rotation of the mirrors will explain everything. I have seen that argued before but never seen anyone make it work. When you know the path length and speed, the time follows. The only attempts I have seen have involved displacement of the point of reflection on the mirror and I think that usually gives a second order effect, certainly not enough to predict what is observed. I'll be very interested to see how you tackle it. If you consider a rotating, four 45deg mirror configuration, the actual source velocity doesn't play any part. It is the peripheral velocity of the first mirror that would contribute to the first c+v effect. The analysis becomes a bit messy after that because all the angles change slightly during the light travel time. They do but the speed of the light leaving each mirror is c+v and the setup is symmetrical about the centre of each light path so the light approaches the next mirror at c+v. Since the mirror is moving at v, it approaches at a relative speed of c. It leaves at c relative to the mirror hence c+v again and so on. If the entire path is covered at c+v, there should be no shift. The change in angles is something to look at but the symmetry argument tends to cancel them out, a greater launch angle corresponds to a greater arrival angle at the next mirror. But the light doesn't arrive at each mirror at c because the mirrors constantly change angle so that their velocity is always slightly less that v when the light reaches them. The small angular variation also causes each reflected beam to be be slightly off 90deg wrt its arrival direction. The thing is very messy. I am pretty sure that the fringe shift would occur even with source dependency. As I say, superficially it all cancels and there should be no shift. You could be right but I know it will be difficult to find an explanation. George. Henri Wilson. See my animations at: http://www.users.bigpond.com/HeWn/index.htm
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#29
July 19th 03, 10:23 AM
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Dependence of the speed of light on the speed of the source.
Henri, I'd like to trim down these posts so I'll press
you for answers on a couple of bits. I don't see why simultaneity should enter into this. To compare the rate of two clocks that to see if they are equal, first synchronise a tick of one clock with a tick of the other. If the next tick from the clocks is also in sync, the clocks are ticking at the same rate. The inequalities for slower or afster rates follow. In your paradox the clocks are in relative motion so even if the are co-located for a first reference tick, they will all be separated for the next tick, and if you have spatially separated clocks, you have to take simultaneity into account. .... You said you didn't see why simultaneity was relevant so I hope you see the role it plays now. Have I explained why it is involved? In SR, simultaneity is not absolute. Whether Doppler is relevant in your theory is not relevant. You cannot disprove any theory if you start with an assumption that conflicts with the theory. Your proof assumes absolute simultaneity hence is invalid for SR. Of course there is absolute simultaneity. That is your opinion, I disagree. It's just that one cannot establish it if one uses light for communication. However if two clcoks ar synchedthen moved apart in flat gravity, then they can be assumed to be in absolute synch No, we do not make such assumptions. You have to demonstrate it by experiment or observation and that evidence supports SR. and, when at rest wrt each other, will establish absolute simultaneity at their locations. Agreed, they would _if_ clocks behaved as you wish. Fine, but none of that is relevant to SR so your proof is still invalid. If you want to prove SR is internally inconsistent, which is what you attempted above, you must limit yourself to the rules of SR. SR is a complete hoax. Again that is your opinion, but your proof is _still_ invalid because it requires an assumption that is contrary to what it tries to disprove. Can you confirm you understand this point so we can move on please. It relies on the misapprehension that falling raindrops take longer too reach the ground when you view them through your car window because they appear to move diagonally. I won't be visiting you then. It must be dangerous living where the rain falls at the speed of light! The point remains, the clocks are moving as they pass that point in orbit so there is a velocity component. That is a purely Newtonian doppler effect. Then you admit the GPS clocks are affected by their motion? No. The clocks are not physically affected by their motion. Their readings have to be adjusted for transverse doppler when observed from Earth, that is all. The Doppler shift is not the same as the Newtonian version. In particular the velocity component is not zero when the motion is perpendicular to the line of sight. That is the SRian view. The Newtonian correction is quite easy to calculate. Really? Please show me how you get a transverse Doppler in Newtonian theory. You have agreed that the clocks have not PHYSICALLY changed due to their movement. I have said they tick at the same rate per unit of proper time. In my view that means they are not physically changed but "physically changed" is not a well defined term and some people would disagree with me even though they would agree with my more explicit statement, hence my care with the wording. The SRian use of the word 'proper' is just a way around admitting that time rate of change is absolute. It is a definition of a measurable quantity. Whether clocks change rate or not is determined by actual measurements. In my opinion they are not physically affected. The rate change comes from projecting from the world line of the clock onto a coordinate axis. But they clearly emit an increased number of ticks per orbit when they are up there compared with before launch. When the ticks are projected onto a ground-based coordinate axis (i.e. where they are measured), the rate is indeed higher. When you then use GR to find their rate against the clock's world lines, we observe that the rate per unit of proper time is unchanged. Hence I sy the clock is not physically affected in that sense. In the sense that the ground-measured rate for a clock in orbit differs from the rate for the same clock prior to launch, it is physically affected. That is why I am careful about wording my answer, "physically affected" can be ambiguous. That means they have increased their physical ticking rates. It has nothing to do with 'time changes' or fancy world lines. snip [GLONASS] does not use a GR correction. Really, I haven't found anything on the subject, can you tell me where you found this information please. I thought it was pretty common knowledge. I will try to find a reference. If it were true, it would be headline news. Even the slightest deviation from GR could be the key to a quantum theory of gravity. If you can find your source I would be fascinated (astonished!). Anyway, the only criterion for GPS accuracy is that all orbiting clocks are in exact synch. 'Time' cancels out in the triangulation method used. No, the GPS system is used to distribute accurate time around the world as well as location information. The clocks have to be kept in sync with the ground clocks as well. The daily correction is simply included in their signals. it's a simply software operation. Right, so why why did you suggest only sync mattered since "'Time' cancels out .." It is vital that all the orbiting clocks are in close synch with each other. Of course, but it is also vital that they are accurately synchronised to Earth time in a manner that allows users to use them as a time reference. Most atomic clocks come with a GPS option for example. Their signals are simply 'software corrected' for current drift. The clocks are built with the GR correction in place and the clock performance is much better than even the smaller velocity-related component. As long as the mean of those corrections is less than the uncertainty in the clock rate, that gives the confirmation of GR. Exactly, and all that could be done with standard amateur astronomy kit. You see, I really was trying to be helpful, not just criticise your idea. You have been helpful and I appreciate that. Your idea is probably just about as feasible as Romer's light speed measurements. Thanks. Synch two clocks together, move them apart and they should remain in absolute synch. Again, you assume nature "should" behave the way you want it to. In fact they always maintain sync in the same way that Einstein's method produces. NO THEY DO NOT. From the Hafele-Keating experiment to the BBC Christmas Lectures a few years ago, every test I know of has been consistent with YES THEY DO and outside the error bars of NO THEY DO NOT. Cite your experimental evidence if you disagree. Again, can you cite anything on this? If you consider a rotating, four 45deg mirror configuration, the actual source velocity doesn't play any part. It is the peripheral velocity of the first mirror that would contribute to the first c+v effect. The analysis becomes a bit messy after that because all the angles change slightly during the light travel time. They do but the speed of the light leaving each mirror is c+v and the setup is symmetrical about the centre of each light path so the light approaches the next mirror at c+v. Since the mirror is moving at v, it approaches at a relative speed of c. It leaves at c relative to the mirror hence c+v again and so on. If the entire path is covered at c+v, there should be no shift. The change in angles is something to look at but the symmetry argument tends to cancel them out, a greater launch angle corresponds to a greater arrival angle at the next mirror. But the light doesn't arrive at each mirror at c because the mirrors constantly change angle so that their velocity is always slightly less that v when the light reaches them. In the co-rotating frame, the light arrives at c and the mirror is not rotating hence there should be no fringe shift. In the lab frame it is not that simple, the speed would be c+v at the centre of the beam, less than c+v on one side and more than c+v on the other because the mirror is rotating so you have to consider constructing wavefronts or some equivalent method for predicting the refelected angle and speed but the result must be the same as in the co-rotating frame analysis since it is just another way of predicting the same experiment. The small angular variation also causes each reflected beam to be be slightly off 90deg wrt its arrival direction. Right, in the co-rotating frame the angles are reduced from 90 degrees because the light paths appear bent. In the lab frame, the angles are reduced because the path is no longer square. However, the change of angles is only needed so that the beam hits the next mirror. It does not affect the speed since, in both frames, there is still symmetry about the normal to the mirror at the point of reflection. The conclusion remains that there should be no fringe shift from either of the effects you mention. The thing is very messy. It needs care certainly, but the symmetry makes it tractable and the result from what I have seen is always a prediction of no fringe shift, contrary to what we observe. George
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#30
July 19th 03, 01:27 PM
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Dependence of the speed of light on the speed of the source.
"George Dishman" wrote in message
... If it were true, it would be headline news. Even the slightest deviation from GR could be the key to a quantum theory of gravity. If you can find your source I would be fascinated (astonished!). To Henri: George's statement is a -very- important point. We -know- that GR must fail at some point, because GR and QM are incompatible. Also, GR predicts things (like singularities) that many people are uncomfortable with, and which they hope might "go away" in a more complete theory. GR is not a religion. Tremendous effort is going on in attempts to discover where GR fails. It hasn't so far, but not for lack of trying. What do you know about Gravity Probe B, or STEP? How about tests of the inverse square law at small distance? Minor Crank
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